This invention relates to bis(perfluoro-t-butyl) peroxide and to a method for its preparation. More particularly, this invention concerns itself with a method for producing bis(perfluoro-t-butyl) peroxide that results in the production of high yields of the pure peroxide as well as a useful by-product without the attendant separation problems associated with prior art methods of preparation.
Perfluoroalkyl peroxides are well known for a wide variety of applications in the chemical, aircraft, space and mining industries. A peroxide of this class that is of particular interest is bis(perfluoro-t-butyl) peroxide. It possesses the following structural formula: EQU (CF.sub.3).sub.3 COOC(CF.sub.3).sub.3 ( 1)
and has been found to be particularly useful as a thermally stable crosslinking agent for unsaturated fluoropolymers. It is also useful as a source of free radicals for polymer initiation, ignition acceleration and as an intermediate in organic synthesis. However, previous methods of preparation often provided low yields as well as undesirable reaction by-products.
In an attempt to overcome the problems associated with previous methods of preparing bis(perfluoro-t-butyl) peroxide, it was found that a free radical condition could be created photolytically and thermally. To be more specific, under photolysis, the homolysis of the bond in perfluoro-t-butyl hypofluorite was found to take place in the presence of tetrafluorohydrazine. The hydrazine component serves as a radical scavenger. This reaction may be presented by the equation: EQU (CF.sub.3).sub.3 COF + N.sub.2 F.sub.4 .fwdarw. (CF.sub.3).sub.3 COOC(CF.sub.3).sub.3 + NF.sub.3 ( 2)
the method represented by equation (2) produces a high yield of the pure peroxide in the absence of separation problems, since the inert volatile NF.sub.3 is readily evacuated at -90.degree. C to leave a pure bis(perfluoro-t-butyl) peroxide residue.